Multi-zone pressure control system

ABSTRACT

A pressure control system that controls the pressure of a fluid in a plurality of zones includes a distribution manifold, at least one main manifold connected to the distribution manifold, and at least one disposable manifold connected to the distribution manifold and the main manifold. The disposable manifold is adapted to be replaced independent of the distribution manifold and the main manifold, and is connected to each zone and to at least one vacuum source. The distribution manifold distributes the fluid to the plurality of zones, so as to cause flow of the fluid into and out of a measurement chamber located within each zone. The main manifold includes, for each zone, a pressure sensor configured to measure pressure in the measurement chamber in that zone, and a control valve configured to regulate the flow of the fluid through that zone.

BACKGROUND

In a number of applications, fluid pressure must be regulated in coupled or non-coupled volumes that are remotely placed with respect to the pressure sensor and the fluid flow actuator. These applications may include, but are not limited to, semiconductor processing systems such as CMP (chemical mechanical polishing) tools. Improving the reliability and serviceability of pressure control systems (PCS) for such applications is a high priority.

SUMMARY

A pressure control system that controls the pressure of a fluid in a plurality of zones includes a distribution manifold, at least one main manifold connected to the distribution manifold, and at least one disposable manifold connected to the distribution manifold and the main manifold. The disposable manifold is adapted to be replaced independent of the distribution manifold and the main manifold, and is connected to each zone and to at least one vacuum source. The distribution manifold is configured to distribute the fluid from a pressurized source of the fluid to the plurality of zones, so as to cause flow of the fluid into and out of a measurement chamber located within each zone. The main manifold includes, for each zone, a pressure sensor configured to measure pressure in the measurement chamber in that zone, and a control valve configured to regulate the flow of the fluid through that zone.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a multi-zone pressure control system in accordance with one embodiment of the present disclosure, including a schematic overview of a pneumatic circuit inside the multi-zone pressure control system.

FIG. 2 illustrates a disposable manifold for the multi-zone pressure control system shown in FIG. 1.

FIG. 3 illustrates a main manifold for the multi-zone pressure control system shown in FIG. 1.

FIG. 4 illustrates a distribution manifold for the multi-zone pressure control system shown in FIG. 1.

FIG. 5 illustrates an overall perspective view of a multi-zone pressure control system in accordance with one embodiment of the present disclosure.

DETAILED DESCRIPTION

Systems and methods are described in which pressure is controlled in a plurality of zones. These systems and methods provide a distribution manifold, at least one manifold, and at least one disposable manifold that is independently replaceable, in order to control the pressure in the plurality of zones. In case a failure, such as slurry contamination, occurs in one of the zones, the systems and methods described below permit only the failed zone to be replaced without having to replace the other zones. Also, such a replacement can be performed directly on the tool, resulting in shorter change over time. The systems and methods described below provide a more robust design for a multi-zone pressure control system.

FIG. 1 is a block diagram of a multi-zone pressure control system 100 in accordance with one embodiment of the present disclosure, and includes a schematic overview of a pneumatic circuit inside the pressure control system 100. The pressure control system 100 is configured to control pressure in a plurality of zones 160, 170, 180, and 190. These zones are independently controllable pressure control zones.

As seen in FIG. 1, the pressure control system 100 includes a manifold assembly that is designed in three sections: a distribution manifold 110, a main manifold assembly 120 comprising a plurality of main manifolds 120-a, . . . , 120-d, and a disposable manifold assembly 130 comprising a plurality of disposable manifolds 130-a, . . . , 130-d. As also seen in FIG. 1 and further described below, the pressure control system 100 provides, for each one of the plurality of zones, a control valve 124, a pressure sensor 122, a first valve 134, a second valve 126, and a third valve 136. The pressure sensor 122 may be a capacitance-based pressure transducer, or other type of pressure transducer.

The distribution manifold 110, also referred to in this patent as a pressure and vacuum distribution manifold or a fluid distribution manifold, does not house any field replaceable parts. In the present patent, the words “distribution manifold,” “fluid distribution manifold”, and “pressure and vacuum distribution manifold” have the same meaning, and are used interchangeably. In the illustrated embodiment, the distribution manifold 110 is fed from a regulated pressure line 112 and a vacuum line 114.

At least one main manifold is coupled to the distribution manifold 120. In the embodiment illustrated in FIG. 1, several main manifolds (120-a, . . . , 120-d), constituting a main manifold assembly 120, are coupled to the distribution manifold 110. In particular, one main manifold is provided for each zone. Each main manifold (120-a . . . 120-d) in the main manifold assembly 120 holds a pressure sensor 122 and a control valve 124, as well as second valve 126. Thus, the number of measurement chambers in the pressure control system 100 equals the numbers of zones.

For each zone, a disposable manifold is also provided, each disposable manifold including a vacuum port 135 that connects to a vacuum source, and a zone port 138 that connects to a respective zone (one of 160, 170, 180, and 190) via a conduit. Each disposable manifold (130-a . . . 130-d) in the disposable manifold assembly 130 is designed to be field removable and independently replaceable, in the event of failures such as slurry contamination.

While in the illustrated embodiment, one main manifold is provided for each one of the plurality of zones, and likewise one disposable manifold is provided for each one of the plurality of zones, other embodiments of the present disclosure may include different combinations of the main manifold and/or the disposable manifold, for the different zones. In general, at least one main manifold and at least one disposable manifold may be provided for each zone.

In one embodiment, the pressure control system 100 may be used for pressure control in a CMP (chemical mechanical polishing) application, and the plurality of zones may be resilient bladders found in internal chambers of a CMP carrier head system. CMP is a commonly used method of planarization of semiconductor substrate surfaces. As a series of silicon layers are sequentially deposited and etched, the outer or uppermost surface of the substrate, i.e., the exposed surface of the substrate, may become increasingly non-planar, and may need to be periodically planarized in order to avoid problems in the photolithographic steps of the integrated circuit fabrication process. Therefore, there may be a need to periodically planarize the substrate surface, and CMP is one of the widely used methods of planarization.

The CMP planarization method may typically require that the substrate be mounted on a carrier or polishing head. The exposed surface of the substrate may be placed against a rotating polishing pad. The carrier head may provide a controllable load, i.e., pressure, on the substrate to push it against the polishing pad. A polishing slurry, including at least one chemically-reactive agent and, in some cases, abrasive particles, may be supplied to the surface of the polishing pad.

An illustrative CMP carrier head system is shown for example in published U.S. application No. US 2004/0250859 to Poulin and Clark, which is hereby incorporated by reference in its entirety. An exemplary CMP carrier head system may be rotatable about its rotation axis, and may include a carrier head connected to a rotation motor. The carrier head may have a number of internal chambers, which are formed at least in part by resilient bladders which expand when the chambers are pressurized, and which contract when a vacuum is created within the chambers. For example, pressurizing a chamber in the carrier head can be used to press a substrate against a rotating polishing pad, while creating a vacuum in the chamber can be used to provide suction for holding the substrate against the carrier head during transfer of the substrate to and from the polishing pad.

The pressure control system 100 may be coupled to the CMP carrier head through a rotary coupling, and may control pressure of a fluid (such as nitrogen) in the plurality of bladders in the carrier head.

FIG. 2 illustrates a disposable manifold 200 for the multi-zone pressure control system 100 shown in FIG. 1. As explained above, the disposable manifold 200 is typically one of a plurality of disposable manifolds in a disposable manifold assembly that includes a plurality of disposable manifolds corresponding to the plurality of zones, as explained above in conjunction with FIG. 1. As shown in FIG. 2, the disposable manifold 200 includes a zone port 220 that connects to a respective zone, for example one of the bladders in a CMP carrier head; a vacuum port 210 that connects to a vacuum source (for example, a vacuum pump); and first and third valves 230 and 240.

The third valve 240 may be opened when it is desired to decrease the pressure of the fluid flowing through the zone to which the disposable manifold is connected. The first valve 230 may be opened when it is desired to slow down a rate of decrease of the pressure of the fluid flowing through the zone to which the disposable manifold is connected.

In a CMP tool, there is typically a barrier in between the pressure control system (PCS) and the wet mixture (slurry) contained in the bladder. The bladder can rupture, due to lack of preventative maintenance, and allow the slurry enter the vacuum line that results in exposure of the valve to the slurry. Over time slurry can cause valve failure. In the event of slurry contamination, the disposable manifold is the only subassembly that would get contaminated. The disposable manifold 200 is designed to be field removable and replaceable in the event of failure, such as slurry contamination in a CMP carrier head. The disposable manifold 200 can be removed while the PCS (pressure control system) 100 is on the CMP tool.

FIG. 3 illustrates a main manifold 300 for a multi-zone pressure control system 100 shown in FIG. 1. The main manifold 300 includes a pressure sensor 320, a control valve 330 that controls flow of the fluid (whose pressure the system 100 is designed to control) throughout a corresponding zone, and a second valve 310. In some embodiments, the main manifold 300, as well as the disposable manifold 200, may also be replaceable.

FIG. 4 illustrates a fluid distribution manifold 400 for a multi-zone pressure control system 100 shown in FIG. 1. The fluid distribution manifold 400 (or pressure and vacuum distribution manifold 400) does not house any field replaceable parts. The fluid distribution manifold 400 includes a pressure inlet port 420 that connects to the pressurized source of fluid, and a vacuum outlet port 410 that connects to a vacuum exhaust. The fluid distribution manifold 400 is configured to distribute the fluid from a pressurized source of fluid to the plurality of zones (illustrated in FIG. 1 as 160, 170, 180, and 190), so as to cause flow of the fluid into and out of a measurement chamber located within each zone. All other manifolds, i.e., the main manifold 300 and the disposable manifold 200, attach to the fluid distribution manifold 400, and are held together via the fluid distribution manifold 400.

FIG. 5 illustrates an overall perspective view of a multi-zone pressure control system 500 in accordance with one embodiment of the present disclosure. In the illustrated configuration, all of the plurality of zones are fed by a single source, with a dump into a single vacuum exhaust.

In sum, systems and methods have been described that allows pressure to be controlled in a plurality of independent pressure control zones. Different zones may have different pressure control ranges over which pressure within respective zones can be controlled.

The design described above introduces a significant improvement over prior methods of controlling pressure in remote zones. Using the modular design for the pressure control system (PCS) would allow to serve the PCS on the tool, which would reduce the tool down time and cost of serviced parts. Using conventional techniques, all zones would have to be replaced, once one zone was exposed to slurry. Using the systems and methods described in the present disclosure, only the failed zone would have to be replaced, and such a replacement can be done on the tool resulting in shorter change over time. The design described above also helps with the robustness of the PCS. The systems and methods described in the present disclosure may be used by customers to regulate, for example, the pressure in the carriage head for CMP applications. The PCS described above may be used in many other applications, including but not limited to semiconductor processing systems.

While certain embodiments have been described of systems and methods for controlling pressure in a plurality of zones, it is to be understood that the concepts implicit in these embodiments may be used in other embodiments as well. The protection of this application is limited solely to the claims that now follow.

In these claims, reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more.” All structural and functional equivalents to the elements of the various embodiments described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference, and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public, regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 U.S.C. §112, sixth paragraph, unless the element is expressly recited using the phrase “means for” or, in the case of a method claim, the element is recited using the phrase “step for.” 

1. A pressure control system for controlling pressure of a fluid in a plurality of zones, the pressure control system comprising: a distribution manifold configured to distribute the fluid from a pressurized source of the fluid to the plurality of zones, so as to cause flow of the fluid into and out of a measurement chamber located within each zone; at least one main manifold connected to the distribution manifold, the main manifold including, for each zone, a pressure sensor configured to measure pressure in the measurement chamber in that zone, and a control valve configured to regulate the flow of the fluid through that zone; and at least one disposable manifold connected to the distribution manifold and the main manifold and adapted to be replaced independent of the distribution manifold and the main manifold, the disposable manifold connected to each zone and to at least one vacuum source.
 2. The pressure control system of claim 1, wherein the disposable manifold comprises: for each zone, a zone port configured to connect the disposable manifold to that zone; and one or more vacuum ports configured to connect the disposable manifold to the vacuum source.
 3. The pressure control system of claim 2, wherein the disposable manifold further comprises: for each zone, a valve connected to the vacuum source and configured to decrease the pressure of the fluid flowing through that zone; and for each zone, a valve configured to slow down a rate of decrease of the pressure of the fluid flowing through that zone.
 4. The pressure control system of claim 1, wherein the main manifold is adapted to be replaced independent of the distribution manifold and the disposable manifold.
 5. The pressure control system of claim 1, wherein the distribution manifold comprises: a pressure inlet port in communication with the pressurized source of the fluid via a pressure line; and a vacuum outlet port that connects the distribution manifold to a vacuum outlet via a vacuum line.
 6. The pressure control system of claim 1, wherein the fluid comprises a gas; and wherein the measurement chamber comprises a bladder in a CMP carrier head.
 7. The pressure control system of claim 6, wherein the gas comprises nitrogen.
 8. The pressure control system of claim 1, wherein at least one of the plurality of zones is located remote from the pressure sensor and from the control valve.
 9. The pressure control system of claim 1, wherein at least some of the zones are coupled to each other.
 10. The pressure control system of claim 1, wherein the at least one main manifold comprises: a main manifold assembly, the main manifold assembly including a plurality of main manifolds, each one of the main manifolds connected to a respective one of the plurality of zones.
 11. The pressure control system of claim 1, wherein the at least one disposable manifold comprises a disposable manifold assembly, the disposable manifold assembly including a plurality of disposable manifolds, each one of the disposable manifolds connected to a respective one of the plurality of zones.
 12. The pressure control system of claim 1, wherein at least some of the zones have pressure control ranges that are different from one another.
 13. A disposable manifold for a multi-zone pressure control system configured to control pressure of a fluid in a plurality of zones, the disposable manifold comprising: one or more vacuum ports configured to connect the disposable manifold to a vacuum source; and for each zone: a zone port configured to connect the disposable manifold to that zone; a valve connected to the vacuum source and configured to decrease the pressure of the fluid flowing through that zone; and a valve configured to slow down a rate of decrease of the pressure of the fluid flowing through that zone; wherein the disposable manifold is connected to a distribution manifold configured to receive the fluid from a pressurized source of the fluid and to cause the fluid to flow through the plurality of zones, and to a main manifold that includes, for each zone, a pressure sensor configured to measure pressure in a measurement chamber in that zone and a control valve configured to regulate the flow of the fluid through that zone; and wherein the disposable manifold is adapted to be replaced independent of the distribution manifold and the main manifold.
 14. A main manifold for a multi-zone pressure control system configured to control pressure of a fluid in a plurality of zones, the main manifold comprising: for each zone: a pressure sensor configured to measure pressure of the fluid in a measurement chamber in that zone, and a control valve configured to regulate the flow of the fluid through that zone; wherein the main manifold is connected to a distribution manifold configured to receive the fluid from a pressurized source of the fluid and to cause the fluid to flow through the plurality of zones, and to a disposable manifold that is adapted to be replaced independent of the distribution manifold and the main manifold and that is in communication with the plurality of zones and with a vacuum source for the pressure control system.
 15. The main manifold of claim 14, wherein the main manifold is adapted to be replaced independent of the distribution manifold and the disposable manifold.
 16. A CMP (chemical mechanical polishing) carrier head comprising: a carrier head including a plurality of bladders; a pressure control system configured to control pressure of a fluid in the bladders, the pressure control system including a distribution manifold, at least one main manifold coupled to the distribution manifold, and at least one disposable manifold adapted to be replaced independent of the distribution manifold; wherein the distribution manifold is configured to distribute the fluid from a pressurized source to the bladders; the main manifold includes, for each bladder, a pressure sensor configured to measure pressure in that bladders and a control valve configured to regulate the flow of the fluid through that bladder; and the disposable manifold is connected to at least one vacuum source and to each bladder; and a rotary coupling between the carrier head and the pressure control system. 